Increase in Breast MRIs Does Not Reflect Recommendations for Appropriate Use
In a study reported in JAMA Internal Medicine, Stout et al assessed use of breast magnetic resonance imaging (MRI) in the community setting from 2000 to 2011. They found a steep increase in use in screening and surveillance, with most women not meeting American Cancer Society (ACS) criteria for breast MRI and many women with high-risk mutations not being screened.
Study Details
This retrospective cohort study involved 10,518 women aged ≥ 20 years enrolled in a not-for-profit health plan and multispecialty group medical practice in New England for ≥ 1 year who had at least one breast MRI between January 1, 2000, and December 31, 2011. The number of breast MRIs was obtained from claims data. Clinical indications of screening, diagnostic evaluation, staging or treatment, and surveillance were determined using a prediction model developed from electronic medical records for a subset of participants (n = 998).
The model had an overall predictive accuracy of 92% in the development set of patients and 82% in the validation set, and positive predictive values in the validation set ranged from 76% to 88% for the four clinical indications. Approximately 16% of screening and surveillance breast MRIs were misclassified as diagnostic by the model. Breast cancer risk status was determined using claims data and by using electronic medical record review in the subset of patients.
Overall Use
The population had a total of 18,215 breast MRIs. Breast MRI use increased approximately 20-fold from 6.5 per 10,000 women in 2000 to 130.7/10,000 in 2009 and then declined to and stabilized at 104.8/10,000 by 2011. From 2003 through 2011, the average annual percentage increase in use was 21%; use increased annually by 46% between 2003 and 2009 and then decreased annually by 10% from 2009 to 2011. Age-specific rates showed similar trends, with women in their 40s and 50s consistently having the highest rates of use.
Use by Indication
For 2003, 2009, and 2011, rates of use were 1.5, 37.3, and 32.3/10,000 for screening; 11.6, 43.4, and 29.8/10,000 for diagnostic evaluation; 3.3, 18.3, and 14.6/10,000 for staging or treatment; and 2.3, 31.7, and 28.1/10,000 for surveillance. Overall, breast cancer risk categories were personal history for 30.1% of women, family history for 51.7%, and genetic mutation for 3.5%. The frequency of BRCA mutation was higher in women receiving screening or surveillance than in those having MRI for other indications (5.1%–5.9% vs 2.0%–3.1%). In total, only 48.4% of women with a known BRCA mutation (180 of 372) received MRI for screening.
A family history of breast cancer was noted in medical claims for 82.0% of women receiving screening MRI but for only approximately 40% of those receiving MRI for other indications. In the subset of women with electronic medical records who received screening or surveillance MRI, only 21.0% (90 of 429) met ACS criteria for breast MRI by having documentation of family history or positive deleterious mutation status indicative of a lifetime risk > 20%.
More women receiving breast MRI for screening (27.7%) or surveillance (44.5%) had multiple MRIs compared with women receiving MRI for diagnostic evaluation (21.0%) or staging or treatment (19.1%). Among the 11% of women having at least three MRIs, 70% were undergoing screening or surveillance.
The investigators concluded, “Breast MRI use increased steeply over 10 years and then stabilized, especially for screening and surveillance among women with family or personal history of breast cancer; most women receiving screening and surveillance breast MRIs lacked documented evidence of meeting ACS criteria, and many women with mutations were not screened. Efforts are needed to ensure that breast MRI use and documentation are focused on those women who will benefit most.”
Natasha K. Stout, PhD, of Harvard Medical School/Harvard Pilgrim Health Care Institute, is corresponding author of the article in JAMA Internal Medicine.
The study was supported by grants from the American Cancer Society and National Institutes of Health. The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
